# This Dockerfile will build an image that is configured to use Fluentd to
# collect container log files from the specified paths and send them to the
# Google Cloud Logging API.
# The environment variable that controls which log files are collected is
# FILES_TO_COLLECT. Files specified in the environment variable should be
# separated by whitespace, as in "/var/log/syslog /var/log/nginx/access.log".
# This configuration assumes that the host performing the collection is a VM
# that has been created with a logging.write scope and that the Logging API
# has been enabled for the project in the Google Developer Console. 

FROM ubuntu:16.04
MAINTAINER Alex Robinson "arob@google.com"

# Disable prompts from apt.
ENV DEBIAN_FRONTEND noninteractive
# Keeps unneeded configs from being installed along with fluentd.
ENV DO_NOT_INSTALL_CATCH_ALL_CONFIG true

# Install the Fluentd agent that knows how to send logs to Google Cloud Logging.
RUN apt-get -q update && \
    apt-get install -y curl && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* && \
    curl -s https://storage.googleapis.com/signals-agents/logging/google-fluentd-install.sh | bash

# Copy the configuration file generator for creating input configurations for
# each file specified in the FILES_TO_COLLECT environment variable.
COPY config_generator.sh /usr/local/sbin/config_generator.sh

# Copy the Fluentd configuration file for collecting from all the inputs
# generated by the config generator and sending them to Google Cloud Logging.
COPY google-fluentd.conf /etc/google-fluentd/google-fluentd.conf

# Run the config generator to get the config files in place and start Fluentd.
# We have to run the config generator at runtime rather than now so that it can
# incorporate the files provided in the environment variable in its config.
CMD /usr/local/sbin/config_generator.sh && /usr/sbin/google-fluentd -qq --use-v1-config --suppress-repeated-stacktrace > /var/log/google-fluentd/google-fluentd.log
